水库诱发地震的震例比较与分析  

COMPARISON AND ANALYSIS ON THE BASIC FEATURES OF RESERVOIR-INDUCED SEISMICITY

作　　者：马文涛[1] 蔺永[1] 苑京立[1] 李海鸥[1] 徐长朋[2] 罗佳宏 

机构地区：[1]中国地震局地质研究所,活动构造和火山重点实验室,北京100029 [2]山东省地震局,济南250014

出　　处：《地震地质》2013年第4期914-929,共16页Seismology and Geology

基　　金："十一五"国家科技支撑计划项目(2008BAC38B04)资助

摘　　要：以水库诱发地震震例数据库为基础,借鉴统计学原理,分析了全球已发震水库的150个震例在地震活动性、震源机制、构造地质和水文地质等方面的主要特征.研究结果表明：水库诱发地震发生在水库周围并在蓄水过程中,多数在距库岸10km范围之内、震源深度＜10km,少数沿着断裂带、溶洞、（温）泉等渗水通道向外延伸至十多km,甚至更远;水库诱发地震活动的频次和震级与库水水位变化呈现相关关系,大部分最大震级地震发生在首次达到最高水位之前或者之后的2～3个蓄水周期内,之后发生最高震级的水库诱发地震概率较少;水库诱发地震序列完整,一般多为“前震-主震-余震”或“前震-震群-余震”型,以1～3级微震居多,因此b值多在1左右;水库诱发地震具有较高的震中烈度、地震动频率和地面峰值加速度,但随距离增加烈度衰减很快;水库地震应力降明显小于同一级别的天然地震应力降,震源尺度大于同一级别的天然地震;水库诱发地震的发震地段具有良好的库水渗透的岩性条件和构造条件,张性断裂带、未胶结的断裂面、岩溶、（温）泉等成为库水的渗透通道.Based on the differences of seismic activity,focal mechanism,geological structure,and hydrologic condition between reservoir induced seismicity （RIS） to natural earthquake,the basic features of reservoir induced earthquake from natural earthquake are studied statistically by the RIS database of 150 cases of reservoir induced earthquakes world-wide,and the results are shown as follows：① Using statistical principle,we find that RIS occur in the areas near the reservoir banks in the impounding period,most of reservoir induced earthquake are distributed within a distance of 10km to the bank,with depth less than 10km,and a few events extend outwards as far as over 10km along fault zones,karst caves,and（thermal） springs; ②The frequency and magnitude of reservoir induced seismicity change with the reservoir water level.Most maximum magnitude earthquakes take place in the period before the first highest water level is reached,or in the following 2-3 impounding stages after the first highest water level,after then,a few would take place; ③The sequence of RIS is complete,usually as ＂foreshock-main shock-aftershock＂ or ＂ foreshock-swarm-aftershock＂,most of them are microseisms of ML1-3,so the b value is larger than natural earthquakes; ④ RIS differ from natural shocks in higher epicenter intensity,higher frequency of ground motion and higher peak ground acceleration,but faster attenuation with distance; ⑤The stress drop of RIS is smaller than that of natural earthquake of the same size,and the source size is larger; ⑥ The RIS occur in areas under lithological and geologic conditions of good permeability.Tensional fracture,tensional fault zone,unconsolidated fault plane,karst,and（thermal）springs are all good water penetration channels.

关 键 词：水库诱发地震 天然地震 震例 库水位 

分 类 号：P316[天文地球—地震学]